An ink jet printer is an example of a printing apparatus that ejects droplets of ink onto a recording medium, such as a sheet of paper, for printing an image on the recording medium. The ink jet printer includes a print engine having one or more ink jet print heads provided with an ink cartridge that accommodates the ink. In operation of the print engine the ink is supplied from the ink cartridge to ejection nozzles of each print head so that a printing operation is performed by ejection of the ink droplets from selected ejection nozzles.
Whenever an ink jet printer remains idle for a duration after printing, print heads may lose water within the ink through the ejection nozzles as the water is absorbed within the capping system, lost to the ambient air, or absorbed within ink that has become less hydrated. As water is lost from the ink, the viscosity may increase, and/or the ink suspension may become unstable, resulting in jetouts. Jetouts typically result in poor image formation quality and require up to several hours of print head maintenance to recover functionality.
In ink jet printers implementing Magnetic Ink Character Recognition (MICR) inks, the MICR particles may settle in, and clog, the print head caps and ambient lines. In either event, service personnel are required to spend additional time manually hydrating the print heads or cleaning jetouts.
Therefore, a print head hydration system is desired.